Lightweight laser femtosecond micro-carving waveguide process

Abstract

The invention belongs to the technical field of laser processing, and particularly relates to a light-weight laser femtosecond micro-engraving waveguide process, which ensures uniform distribution of modified points on a waveguide path and avoids breakpoints and defects by accurately adjusting the energy density, pulse interval and scanning speed of laser pulses, thereby realizing continuity of the waveguide path. Through fine adjustment of the waveguide path, it is ensured that the refractive index on the waveguide path changes uniformly, the transmission efficiency of the waveguide is improved, loss is reduced, and therefore the overall optical performance of the waveguide is improved. The technological process is simple and efficient, a complex photomask and a wet etching process are not needed, the production cost is reduced, the production efficiency is improved, the problems of discontinuous waveguide paths and unstable optical performance in the prior art can be effectively solved, and the method has wide application prospects.

Description

[0001] The invention belongs to the technical field of laser processing, and in particular relates to a lightweight laser femtosecond micro-engraving waveguide process. Background Art

[0002] In the field of modern optical communications and optical interconnection, optical fibers and waveguide devices are widely used in various high-performance systems due to their advantages such as low loss, high bandwidth and anti-electromagnetic interference. Traditional waveguide manufacturing methods mainly include photolithography, ion exchange, chemical vapor deposition and other technologies. Although these methods can produce high-quality waveguides, there are some significant limitations in the manufacturing process. For example, photolithography technology requires complex photomasks and wet etching processes, which are not only costly, but also complex, making it difficult to achieve high-precision and high-efficiency production. Methods such as ion exchange and chemical vapor deposition may introduce additional impurities and defects, affecting the optical properties of the waveguide.

[0003] In recent years, femtosecond laser direct writing technology has attracted widespread attention due to its high precision, maskless, non-contact and three-dimensional processing capabilities. Femtosecond laser direct writing technology can form local refractive index changes inside transparent or semi-transparent materials by generating nonlinear absorption inside the material, thereby constructing a three-dimensional waveguide structure. However, the existing femtosecond laser direct writing technology still faces some challenges in practical applications, especially in terms of the continuity and optical performance of the waveguide. For example, due to improper selection of laser pulse parameters, problems such as discontinuity of the waveguide path and uneven refractive index changes may occur, which in turn affects the transmission efficiency and loss of the waveguide.

[0004] The main problems of existing femtosecond laser direct writing technology in the waveguide manufacturing process are the discontinuity of the waveguide path and the instability of optical performance. Specifically,

[0005] Discontinuity of the waveguide path: Improper selection of laser pulse parameters (such as energy density, pulse interval, and scanning speed) may lead to uneven distribution of modified points on the waveguide path, forming breakpoints or defects, which will affect the continuity of the waveguide.

[0006] Instability in optical performance: Non-uniform refractive index variations along the waveguide path can lead to low transmission efficiency and increased losses, thus affecting the overall optical performance of the waveguide. Summary of the invention

[0007] The purpose of the present invention is to provide a lightweight laser femtosecond micro-engraving waveguide process, which optimizes the continuity and optical performance of the waveguide path by precisely controlling the laser pulse parameters, so as to solve the problems raised in the above background technology.

[0008] To achieve the above object, the present invention adopts the following technical solution: a lightweight laser femtosecond micro-engraving waveguide process, comprising the following steps:

[0009] Select a transparent or translucent material as the substrate that can withstand femtosecond laser pulses without causing thermal damage;

[0010] On the selected substrate, a high-precision femtosecond laser is used to emit laser pulses, and ablation of the material surface is avoided during the emission of the laser pulses, while ensuring nonlinear absorption inside the material;

[0011] According to the position where the nonlinear absorption occurs, the focusing depth of the femtosecond laser is adjusted so that the laser focus is located at the level where the refractive index change is expected to occur inside the material;

[0012] In combination with the set focus depth, a series of discrete modified points are formed by controlling the number and interval of laser pulses, and the modified points form a predetermined lattice structure inside the material;

[0013] Using the formed lattice structure, by continuously changing the position of the laser focus, a continuous waveguide path is constructed, the waveguide path has a predetermined geometric shape, and based on the constructed waveguide path, the laser pulse parameters are optimized;

[0014] The waveguide path is adjusted by optimizing the laser pulse parameters to achieve the control of the waveguide shape and size, and then the entire waveguide structure is quality inspected to check whether the continuity and optical performance of the waveguide meet the design standards;

[0015] According to the results of the quality inspection, the waveguide structures that do not meet the standards are corrected until all waveguides meet the preset performance indicators.

[0016] Preferably, the method of selecting a transparent or translucent material as a substrate that can withstand femtosecond laser pulses without causing thermal damage comprises the following steps:

[0017] On the selected substrate material, measure the initial refractive index n of the material o , and record the material thickness d and transmittance T o ;

[0018] Based on the measured parameters, the relationship between the laser pulse energy density E and the refractive index change Δn inside the material is calculated, Δn=kE, where k is the nonlinear coefficient of the material;

[0019] Determine the optimal value of the laser pulse energy density E to ensure that the refractive index change Δn inside the material reaches a predetermined value;

[0020] Under the determined optimal energy density E, the refractive index change Δn inside the material is verified, and the laser parameters are adjusted to optimize the transmission efficiency of the waveguide.

[0021] Preferably, the method of emitting laser pulses on the selected substrate using a high-precision femtosecond laser comprises the following steps:

[0022] First, determine the repetition frequency f and pulse width τ of the laser pulse, record the absorption coefficient α of the material, and calculate the peak power P of the laser pulse inside the material. peak , using the formula P peak =E / (τ·A), where A is the laser spot area;

[0023] Utilize peak power P peak , determine the upper limit of the laser pulse energy density E to avoid ablation of the material surface, using the formula E max =P peak ·τ·A;

[0024] At the determined upper limit E max The laser pulse energy density E is adjusted to ensure nonlinear absorption inside the material while avoiding thermal damage.

[0025] Preferably, adjusting the focusing depth of the femtosecond laser according to the position where the nonlinear absorption is generated comprises the following steps:

[0026] Measure the material thickness d and the initial position z of the laser focus o , and record the refractive index gradient of the material Calculate the focal depth z of the laser focus inside the material f , using the formula where Δn is the refractive index change;

[0027] Using the focus depth f Adjust the focusing system of the femtosecond laser so that the laser focus is precisely located at the level inside the material where the refractive index change is expected to occur;

[0028] After adjusting the focal depth z f Under the given conditions, verify the position of the laser focus and make fine adjustments if necessary.

[0029] Preferably, the focus depth set in combination forms a series of discrete modified points by controlling the number and interval of laser pulses, comprising the following steps:

[0030] Determine the number of laser pulses N and the pulse interval t, and record the laser spot diameter D, and calculate the distance s between adjacent modified points using the formula s = v·t, where v is the laser scanning speed;

[0031] The interval t of the laser pulses is adjusted by using the step distance s to ensure that the modified points are evenly distributed inside the material to form a predetermined lattice structure;

[0032] Under the adjusted pulse interval t, the laser pulse parameters are fine-tuned as needed to optimize the uniformity and density of the lattice structure.

[0033] Preferably, the method of utilizing the formed lattice structure to construct a continuous waveguide path by continuously changing the position of the laser focus comprises the following steps:

[0034] Determine the predetermined geometry of the waveguide path, record the total length L of the path and the radius of curvature R of the path, and calculate the moving speed v of the laser focus on the path using the formula where t total is the time required to complete the path;

[0035] Using the moving speed v, the scanning speed of the laser is adjusted to ensure that the laser focus moves continuously and evenly on the path to form a continuous waveguide path;

[0036] At the adjusted scanning speed v, fine-tune the laser parameters as needed.

[0037] Preferably, the step of optimizing the laser pulse parameters based on the constructed waveguide path comprises the following steps:

[0038] Measuring the initial transmission efficiency η of the waveguide path o and loss coefficient α o ;

[0039] Calculate the effect of laser pulse energy density E on transmission efficiency η, using the formula η=η o exp(-α o L), where L is the length of the waveguide path, the laser pulse energy density E is adjusted using the formula to maximize the transmission efficiency η and minimize the loss coefficient α o ;

[0040] Under the adjusted laser pulse energy density E, the laser parameters are optimized.

[0041] Preferably, the adjusting the waveguide path by optimizing the laser pulse parameters comprises the following steps:

[0042] Determine the predetermined geometry and dimensions of the waveguide path, record the width and height h of the waveguide, and calculate the scanning path length L of the laser focus on the waveguide path scan , using the formula L scan =L+2h, where L is the total length of the waveguide path;

[0043] Using the scan path length L scan , adjust the repetition frequency f of the laser pulse to ensure that the laser focus is evenly distributed on the waveguide path, using the formula f = L scant, where v is the laser scanning speed and t is the pulse interval;

[0044] Under the adjusted repetition frequency f, the laser parameters are fine-tuned as needed to achieve control of the waveguide shape and size.

[0045] Preferably, the quality inspection of the entire waveguide structure comprises the following steps:

[0046] Measure the transmittance T and reflectance R of the waveguide, and record the total loss α of the waveguide, calculate the transmission efficiency η of the waveguide, using the formula

[0047] The transmission efficiency η is used to evaluate the continuity and optical performance of the waveguide to ensure that it meets the design standards. Based on the evaluated results, the overall performance of the waveguide is verified and optimized and adjusted as needed.

[0048] Preferably, the step of correcting the waveguide structure that does not meet the standards according to the result of the quality inspection until all waveguides meet the preset performance indicators comprises the following steps:

[0049] Based on the quality inspection results, determine the waveguide structures that do not meet the standards in the waveguide, and record the locations and defect types of these parts;

[0050] Based on the defect information, analyze the cause of the defect and use the formula ΔE=E opt -E actual , where E opt is the optimized laser pulse energy density, E actual is the actual laser pulse energy density used;

[0051] Using the analysis results, adjust the laser pulse parameters, including energy density E, pulse interval t and scanning speed v, to eliminate or reduce defects;

[0052] Under the adjusted parameter conditions, the waveguide is reprocessed and the continuity and optical performance of the waveguide are verified until all waveguides meet the preset performance indicators.

[0053] Technical effects and advantages of the present invention: Compared with the prior art, the lightweight laser femtosecond micro-engraving waveguide process proposed by the present invention has the following advantages:

[0054] The present invention ensures uniform distribution of modified points on the waveguide path by precisely adjusting the energy density, pulse interval and scanning speed of the laser pulse, avoids the generation of breakpoints and defects, and thus realizes the continuity of the waveguide path; through fine adjustment of the waveguide path, it ensures uniform change of the refractive index on the waveguide path, improves the transmission efficiency of the waveguide, reduces the loss, and thus improves the overall optical performance of the waveguide; the process flow of the present invention is simple and efficient, does not require complicated photomasks and wet etching processes, reduces production costs, improves production efficiency, can effectively solve the problems of discontinuous waveguide paths and unstable optical performance in the prior art, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 The present invention is a flow chart of a lightweight laser femtosecond micro-engraving waveguide process. DETAILED DESCRIPTION

[0056] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. The specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0057] The present invention provides Figure 1 A lightweight laser femtosecond micro-engraving waveguide process shown includes the following steps:

[0058] Step 1: Select a transparent or translucent material that can withstand femtosecond laser pulses without thermal damage as the substrate. For example, select silicon dioxide (SiO2) glass as the substrate material because silicon dioxide glass has good optical transparency and mechanical stability and is suitable for femtosecond laser micromachining. On the selected substrate material, use an Abbe refractometer to measure the initial refractive index n of the substrate material. o , use a micrometer to measure the thickness of the substrate material, use a UV-visible spectrometer to measure the transmittance of the substrate material, and record the thickness d and transmittance T of the material o ; Assume that the measured initial refractive index is n o =1.45, d=1, T o =90%, nonlinear coefficient is k=10 -10 m 2 / J.

[0059] Based on the measured parameters, the relationship between the laser pulse energy density E and the refractive index change Δn inside the material is calculated, Δn=kE, where k is the nonlinear coefficient of the material; for example, if the refractive index change inside the material is expected to reach Δn=10 -3 , then the required laser pulse energy density E is:

[0060]

[0061] Determine the optimal value of the laser pulse energy density E to ensure that the refractive index change Δn inside the material reaches a predetermined value; Based on the above calculation, the optimal value of the laser pulse energy density is determined to be E opt =10 7 J / m 2 This value can ensure that the refractive index change inside the material reaches the predetermined value and avoid thermal damage to the material surface.

[0062] Under the condition of the determined optimal energy density E, the refractive index change Δn inside the material is verified, and the laser parameters are adjusted to optimize the transmission efficiency of the waveguide. opt Under these conditions, a femtosecond laser is used to perform preliminary processing inside the substrate material, and then an ellipsometer is used to measure the refractive index change inside the material. Assuming that the actual refractive index change measured is Δn actual =0.95×10 -3 .

[0063] According to the actual measured refractive index change, adjust the laser pulse energy density E. For example, if the actual refractive index change is lower than the expected value, the laser pulse energy density can be appropriately increased. Assume that the adjusted energy density is E new =1.05×10 7 J / m 2 After adjusting the energy density E new Under these conditions, the waveguide was reprocessed and the transmission efficiency and loss of the waveguide were verified through experiments.

[0064] Step 2: On the selected substrate, a high-precision femtosecond laser is used to emit laser pulses, in which ablation of the material surface is avoided while ensuring nonlinear absorption inside the material; further including:

[0065] First, determine the repetition frequency f and pulse width τ of the laser pulse, record the absorption coefficient α of the material, and calculate the peak power P of the laser pulse inside the material. peak , using the formula P peak =E / (τ·A), where A is the laser spot area;

[0066] Utilize peak power P peak, determine the upper limit of the laser pulse energy density E to avoid ablation of the material surface, using the formula E max =P peak ·τ·A;

[0067] At the determined upper limit E max The laser pulse energy density E is adjusted to ensure nonlinear absorption inside the material while avoiding thermal damage.

[0068] By precisely controlling the repetition frequency, pulse width and energy density of the laser pulses, we can ensure that the laser pulses produce nonlinear absorption inside the material while avoiding ablation of the material surface. This helps to protect the integrity and optical properties of the material surface.

[0069] By adjusting the laser pulse energy density, sufficient nonlinear absorption is ensured inside the material, thereby forming the required refractive index change inside the material. This helps to build a high-quality waveguide path. By precisely controlling the laser pulse parameters, the continuity and uniformity of the waveguide path are optimized, the transmission efficiency of the waveguide is improved, and the loss is reduced.

[0070] This embodiment simplifies the waveguide manufacturing process by precisely controlling laser pulse parameters, reduces unnecessary tests and adjustments, and improves production efficiency and yield.

[0071] Through the above specific implementation methods, the femtosecond laser micromachining process can be effectively controlled and optimized to ensure the high quality and high performance of the waveguide.

[0072] Step 3: According to the location where nonlinear absorption occurs, the focusing depth of the femtosecond laser is adjusted so that the laser focus is located at the level where the refractive index change is expected to occur inside the material; further including:

[0073] Measure the material thickness d and the initial position z of the laser focus o , and record the refractive index gradient of the material Calculate the focal depth z of the laser focus inside the material f , using the formula Where Δn is the change in refractive index. Through this formula, the specific position of the laser focus inside the material can be determined.

[0074] Use a micrometer to measure the thickness of the substrate material and record the value. Ensure that the measurement result is accurate for subsequent calculations and adjustments. Use a microscope or laser positioning system to measure the initial position of the laser focus on the material surface and record the value. Ensure the measurement accuracy of the initial position to avoid errors in subsequent adjustments. Obtain the refractive index gradient of the substrate material through experiments or by consulting relevant literature, and record the value. The refractive index gradient reflects the change of the refractive index inside the material with position, which is crucial for accurately adjusting the focus depth.

[0075] Using the focus depth f Adjust the focusing system of the femtosecond laser so that the laser focus is precisely located at the level inside the material where the refractive index change is expected to occur. This adjustment can be made using manual adjustment or an automatic focus system. Ensure that the position of the laser focus is stable and accurate during the adjustment process.

[0076] After adjusting the focal depth z f Verify the position of the laser focus under the conditions and make fine adjustments as needed. Use a microscope or other high-precision measuring tool to verify the actual position of the laser focus under the adjusted focus depth conditions. Make sure that the laser focus is actually at the calculated focus depth. If the verification results show that the position of the laser focus deviates from the expected value, you can make fine adjustments based on the deviation. Ensure that the position of the laser focus is accurate through repeated verification and fine adjustments.

[0077] By accurately measuring the thickness of the material, the initial position of the laser focus, and the refractive index gradient of the material, combined with the refractive index change, the focusing depth of the laser focus inside the material can be accurately calculated. This ensures that the laser focus can be precisely located at the level where the refractive index change is expected to form inside the material, thereby achieving high-precision waveguide path construction.

[0078] Precise focus depth control helps to form a uniform and continuous refractive index change inside the material, thereby improving the quality of the waveguide path. This not only ensures the continuity of the waveguide path, but also improves the optical performance of the waveguide, such as transmission efficiency and loss. By precisely adjusting the position of the laser focus, excessive concentration of the laser focus on the material surface is avoided, thereby reducing thermal damage to the material surface. This helps to protect the surface integrity of the material and extend the service life of the material.

[0079] This embodiment simplifies the waveguide path construction process by accurately controlling and verifying the position of the laser focus, reduces unnecessary tests and adjustments, and improves production efficiency and yield.

[0080] Step 4: Combined with the set focus depth, a series of discrete modified points are formed by controlling the number and interval of laser pulses, and the modified points form a predetermined lattice structure inside the material;

[0081] Determine the number of laser pulses based on the length of the waveguide path and the required density of modified points. Make sure that the number of pulses is large enough to form a continuous and uniform lattice structure. Determine the interval of laser pulses based on the laser scanning speed and the required point spacing. The pulse interval should be moderate, neither too dense nor too sparse, to ensure that the modified points are evenly distributed inside the material. Use a microscope to measure the diameter of the laser spot and record the value. The laser spot diameter determines the size of each modified point and has an important influence on the uniformity and density of the lattice structure.

[0082] First, determine the number of laser pulses N and the pulse interval t, and record the laser spot diameter D, calculate the distance s between adjacent modified points, and use the formula s = v·t, where v is the laser scanning speed. Through this formula, the distance between each modified point can be determined to ensure that they are evenly distributed inside the material; according to the performance of the femtosecond laser and the design of the waveguide path, determine the laser scanning speed. The scanning speed should be moderate to ensure the stability and uniformity of the laser focus inside the material. Using the laser scanning speed and pulse interval, calculate the distance between adjacent modified points.

[0083] The step distance s is used to adjust the interval t of the laser pulses to ensure that the modified points are evenly distributed inside the material to form a predetermined lattice structure; under the adjusted pulse interval t, the laser pulse parameters are fine-tuned as needed to optimize the uniformity and density of the lattice structure.

[0084] Adjust the interval of the laser pulses according to the calculated distance between adjacent modified points. Ensure that the pulse interval is moderate to form the predetermined lattice structure. This adjustment can be achieved by manual adjustment or using an automatic control system. Under the adjusted pulse interval conditions, use a microscope or other high-precision measurement tools to verify the distribution of the modified points inside the material. Ensure that the modified points are evenly distributed to form the predetermined lattice structure.

[0085] According to the verification results, if the distribution of the modified points is uneven or the density does not meet the requirements, the parameters of the laser pulse, such as energy density, pulse interval and scanning speed, can be fine-tuned. Through repeated verification and fine-tuning, it is ensured that the modified points are evenly distributed inside the material to form a high-quality lattice structure.

[0086] By precisely controlling the number and interval of laser pulses, as well as adjusting the laser scanning speed, it is possible to ensure that the modified points are evenly distributed inside the material. This helps to form a continuous and uniform lattice structure and improve the quality of the waveguide path. By fine-tuning the laser pulse parameters, the density of the lattice structure can be optimized to ensure that the size and spacing of each modified point meet the design requirements. This not only improves the uniformity of the lattice structure, but also enhances the stability and reliability of the waveguide path. Evenly distributed modified points help to form a continuous waveguide path and reduce breakpoints and defects in the path. This improves the continuity of the waveguide path and ensures efficient transmission of optical signals within the waveguide.

[0087] This embodiment simplifies the construction process of the lattice structure by accurately controlling and verifying the laser pulse parameters, reduces unnecessary tests and adjustments, and improves production efficiency and yield rate.

[0088] Step 5: Using the formed lattice structure, by continuously changing the position of the laser focus, a continuous waveguide path is constructed, the waveguide path has a predetermined geometric shape, and based on the constructed waveguide path, the laser pulse parameters are optimized; further comprising:

[0089] According to the actual application requirements, determine the predetermined geometric shape of the waveguide path. Common geometric shapes include straight lines, curves, rings, etc. Determine the predetermined geometric shape of the waveguide path, record the total length L of the path and the radius of curvature R of the path, calculate the moving speed v of the laser focus on the path, and use the formula where t total is the time required to complete the path; using this formula, the speed at which the laser focus moves along the path can be determined to ensure that it moves continuously and evenly along the path.

[0090] Using the moving speed v, adjust the scanning speed of the laser to ensure that the laser focus moves continuously and evenly on the path to form a continuous waveguide path; ensure that the scanning speed is moderate to form a continuous waveguide path. This adjustment can be achieved by manual adjustment or using an automatic control system.

[0091] Verify the continuity of the path: Use a microscope or other high-precision measurement tool to verify the continuity and geometry of the waveguide path under the adjusted scanning speed. Ensure that the laser focus moves continuously and evenly on the path to form a high-quality waveguide path.

[0092] Under the adjusted scanning speed v, fine-tune the laser parameters as needed. Based on the verification results, if it is found that the continuity or geometry of the waveguide path does not meet the requirements, the laser parameters such as laser pulse energy density, pulse interval and scanning speed can be fine-tuned. Through repeated verification and fine-tuning, ensure that the continuity and geometry of the waveguide path meet the design requirements.

[0093] By precisely controlling the moving speed of the laser focus, we ensure that the laser focus moves continuously and evenly along the path, forming a continuous waveguide path. This helps reduce breakpoints and defects in the path and improves the continuity of the waveguide path.

[0094] By adjusting the scanning speed of the laser, the geometric shape of the waveguide path meets the design requirements. Whether it is a straight line, curve or circular path, the predetermined geometric shape can be accurately formed to improve the stability and reliability of the waveguide path. A continuous and uniform waveguide path helps to improve the transmission efficiency of the optical signal in the waveguide and reduce the loss. This not only improves the optical performance of the waveguide, but also ensures the efficient transmission of the optical signal.

[0095] Further comprising: measuring the initial transmission efficiency η of the waveguide path o and loss coefficient α o ;

[0096] Calculate the effect of laser pulse energy density E on transmission efficiency η, using the formula η=η o exp(-α o L), where L is the length of the waveguide path, the laser pulse energy density E is adjusted using the formula to maximize the transmission efficiency η and minimize the loss coefficient α o ; Use a spectrometer or optical power meter to measure the initial transmission efficiency of the waveguide path. The transmission efficiency reflects the transmission capacity of the optical signal in the waveguide and is an important indicator for evaluating the performance of the waveguide. Determine the initial loss coefficient of the waveguide path through experiments or theoretical calculations. The loss coefficient reflects the attenuation of the optical signal during propagation in the waveguide and has an important influence on the optical performance of the waveguide.

[0097] Optimize the laser parameters under the adjusted laser pulse energy density E. According to the calculation results, adjust the laser pulse energy density to maximize the transmission efficiency and minimize the loss coefficient. The optimal value can be found by gradually increasing or decreasing the laser pulse energy density and observing the changes in the transmission efficiency and loss coefficient. Under the adjusted laser pulse energy density, re-measure the transmission efficiency and loss coefficient of the waveguide path to ensure that the optimized waveguide path has higher transmission efficiency and lower loss.

[0098] After determining the optimal laser pulse energy density, other laser parameters such as pulse interval, scanning speed and repetition frequency are further optimized. Through multiple experiments and verifications, all parameters are ensured to be in the optimal state to achieve the best performance of the waveguide path. According to the experimental results, the laser parameters are fine-tuned to ensure that the transmission efficiency and loss coefficient of the waveguide path are in the optimal state.

[0099] By precisely adjusting the laser pulse energy density, the transmission efficiency of the waveguide path can be significantly improved. The optimized waveguide path can transmit optical signals more efficiently, reduce signal loss, and improve overall performance.

[0100] By optimizing the laser pulse energy density and other parameters, the loss coefficient of the waveguide path can be effectively reduced. A lower loss coefficient means that the optical signal has less attenuation in the waveguide and a longer transmission distance, which is suitable for long-distance optical communications and high-precision optical systems. The optimized waveguide path has higher stability and reliability. The continuous and uniform waveguide path reduces fluctuations and noise in signal transmission and improves the overall stability of the system.

[0101] Step 6: Through the parameter optimization process, the waveguide path is adjusted to achieve the control of the waveguide shape and size. After that, the quality inspection of the entire waveguide structure is carried out to check whether the continuity and optical performance of the waveguide meet the design standards;

[0102] The waveguide path is adjusted through a parameter optimization process, which includes the following steps:

[0103] According to the actual application requirements, determine the predetermined geometric shape and size of the waveguide path. Common geometric shapes include straight lines, curves, rings, etc. Record the width and height h of the waveguide, and calculate the scanning path length L of the laser focus on the waveguide path scan , using the formula L scan =L+2h, where L is the total length of the waveguide path; through this formula, the scanning path length of the laser focus on the waveguide path can be determined to ensure that the laser focus is evenly distributed on the waveguide path.

[0104] Using the scan path length L scan , adjust the repetition frequency f of the laser pulse to ensure that the laser focus is evenly distributed on the waveguide path, using the formula f = L scan t, where v is the laser scanning speed and t is the pulse interval;

[0105] Fine-tune laser parameters such as laser pulse energy density, pulse interval, and scanning speed as needed under the adjusted repetition frequency f. Ensure that the shape and size of the waveguide path meet the design requirements through repeated verification and fine-tuning to achieve the control of the waveguide shape and size. Use a microscope or other high-precision measurement tools to verify the shape and size of the waveguide path. Ensure that the width and height of the waveguide path are uniform, without obvious defects or discontinuities.

[0106] By accurately calculating the scanning path length of the laser focus and adjusting the repetition frequency of the laser pulse, it is possible to ensure that the laser focus is evenly distributed on the waveguide path. This helps to precisely control the shape and size of the waveguide, ensuring that the geometry of the waveguide path meets the design requirements.

[0107] By fine-tuning the laser parameters, the uniformity of the waveguide path can be optimized. A uniform waveguide path helps improve the transmission efficiency of the optical signal in the waveguide, reduce signal loss, and improve overall performance.

[0108] The quality inspection of the entire waveguide structure includes the following steps:

[0109] Use a spectrometer or optical power meter to measure the transmittance T and reflectance R of the waveguide, and record the total loss α of the waveguide to calculate the transmission efficiency η of the waveguide using the formula Through this formula, the transmission efficiency of the waveguide can be evaluated to ensure that it meets the design standards.

[0110] The transmittance reflects the intensity of the optical signal after passing through the waveguide and is an important indicator for evaluating the transmission efficiency of the waveguide. The reflectivity reflects the reflection of the optical signal at the waveguide entrance and has an important influence on the optical performance of the waveguide. The total loss reflects the attenuation of the optical signal during propagation in the waveguide and is an important parameter for evaluating the performance of the waveguide.

[0111] Using the transmission efficiency η, use a microscope or other high-precision measurement tools to evaluate the continuity and optical performance of the waveguide to ensure that it meets the design standards. Based on the evaluation results, verify the overall performance of the waveguide and optimize and adjust as needed. Based on the verification results, if it is found that the continuity or optical performance of the waveguide does not meet the requirements, further optimization and adjustment can be performed. For example, adjust the laser pulse energy density, pulse interval and scanning speed to improve the transmission efficiency of the waveguide and reduce the loss.

[0112] Step 7: According to the quality inspection results, the waveguide structure that does not meet the standards is corrected until all waveguides meet the preset performance indicators. Further including:

[0113] Based on the quality inspection results, identify the waveguide structures that do not meet the standards in the waveguide and record the location and defect types of these parts; for example, record the breakpoints, discontinuous areas, or high-loss areas in the waveguide path. Record the defect types of these parts, such as surface ablation, internal bubbles, uneven refractive index changes, etc. Ensure that the records are detailed for subsequent analysis and processing.

[0114] According to the recorded defect location and type, analyze the cause of the defect. Common causes include insufficient or too high laser pulse energy density, improper pulse interval, too fast or too slow scanning speed, etc. Based on the defect information, analyze the cause of the defect and use the formula ΔE=E opt -E actual , where E opt is the optimized laser pulse energy density, E actual is the actual laser pulse energy density used; through this formula, we can analyze the effect of laser pulse energy density on waveguide defects and find out the specific causes of the defects.

[0115] Using the analysis results, adjust the laser pulse parameters, including energy density E, pulse interval t and scanning speed v, to eliminate or reduce defects. If the energy density is insufficient, increase the energy density appropriately; if the energy density is too high, reduce the energy density appropriately;

[0116] Adjust the interval of laser pulses to ensure that the modified points are evenly distributed inside the material. If the pulse interval is too small, the modified points may overlap; if the pulse interval is too large, it may cause breakpoints between the modified points. Adjust the laser scanning speed v to ensure that the laser focus moves continuously and evenly on the waveguide path. If the scanning speed is too fast, the modified points may be unevenly distributed; if the scanning speed is too slow, it may increase the processing time and affect production efficiency.

[0117] Under the adjusted parameter conditions, re-process the waveguide and verify the continuity and optical performance of the waveguide until all waveguides meet the preset performance indicators. Use a microscope or other high-precision measurement tools to verify the continuity and optical performance of the waveguide. Ensure that the transmission efficiency and loss coefficient of the waveguide path meet the design standards. Based on the verification results, if the continuity or optical performance of the waveguide is still insufficient, the laser parameters can be further fine-tuned until all waveguides meet the preset performance indicators.

[0118] By precisely analyzing and adjusting the laser pulse parameters, defects in the waveguide, such as breakpoints, discontinuous areas, and high-loss areas, can be effectively eliminated or reduced. This helps improve the continuity and optical performance of the waveguide.

[0119] The optimized waveguide path has higher transmission efficiency and lower loss coefficient. This not only improves the optical performance of the waveguide, but also ensures the efficient transmission of optical signals, making it suitable for various high-performance optical systems.

[0120] Through detailed defect analysis and parameter adjustment, the stability and reliability of the waveguide path can be ensured. The continuous and uniform waveguide path reduces fluctuations and noise in signal transmission and improves the overall stability of the system.

[0121] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A lightweight laser femtosecond micro-engraving waveguide process, characterized in that: The following steps are involved: Select a transparent or translucent material as the substrate that can withstand femtosecond laser pulses without causing thermal damage; On the selected substrate, a high-precision femtosecond laser is used to emit laser pulses, and ablation of the material surface is avoided during the emission of the laser pulses, while ensuring nonlinear absorption inside the material; According to the position where the nonlinear absorption occurs, the focusing depth of the femtosecond laser is adjusted so that the laser focus is located at the level where the refractive index change is expected to occur inside the material; In combination with the set focus depth, a series of discrete modified points are formed by controlling the number and interval of laser pulses, and the modified points form a predetermined lattice structure inside the material; Using the formed lattice structure, by continuously changing the position of the laser focus, a continuous waveguide path is constructed, the waveguide path has a predetermined geometric shape, and based on the constructed waveguide path, the laser pulse parameters are optimized; The waveguide path is adjusted by optimizing the laser pulse parameters to achieve the control of the waveguide shape and size, and then the entire waveguide structure is quality inspected to check whether the continuity and optical performance of the waveguide meet the design standards; According to the results of the quality inspection, the waveguide structures that do not meet the standards are corrected until all waveguides meet the preset performance indicators.

2. A lightweight laser femtosecond micro-engraving waveguide process according to claim 1, characterized in that: The method of selecting a transparent or translucent material as a substrate that can withstand femtosecond laser pulses without causing thermal damage comprises the following steps: On the selected substrate material, measure the initial refractive index n of the material o , and record the material thickness d and transmittance T o ; Based on the measured parameters, the relationship between the laser pulse energy density E and the refractive index change Δn inside the material is calculated, Δn=kE, where k is the nonlinear coefficient of the material; Determine the optimal value of the laser pulse energy density E to ensure that the refractive index change Δn inside the material reaches a predetermined value; Under the determined optimal energy density E, the refractive index change Δn inside the material is verified, and the laser parameters are adjusted to optimize the transmission efficiency of the waveguide.

3. A lightweight laser femtosecond micro-engraving waveguide process according to claim 2, characterized in that: The method of emitting laser pulses on the selected substrate using a high-precision femtosecond laser comprises the following steps: First, determine the repetition frequency f and pulse width τ of the laser pulse, record the absorption coefficient α of the material, and calculate the peak power P of the laser pulse inside the material. peak , using the formula P peak =E / (τ·A), where A is the laser spot area; Utilize peak power P peak , determine the upper limit of the laser pulse energy density E to avoid ablation of the material surface, using the formula E max =P peak ·τ·A; At the determined upper limit E max The laser pulse energy density E is adjusted to ensure nonlinear absorption inside the material while avoiding thermal damage.

4. A lightweight laser femtosecond micro-engraving waveguide process according to claim 3, characterized in that: The method of adjusting the focusing depth of the femtosecond laser according to the position where the nonlinear absorption is generated comprises the following steps: Measure the material thickness d and the initial position z of the laser focus o , and record the refractive index gradient of the material Calculate the focal depth z of the laser focus inside the material f , using the formula where Δn is the refractive index change; Using the focus depth f Adjust the focusing system of the femtosecond laser so that the laser focus is precisely located at the level inside the material where the refractive index change is expected to occur; After adjusting the focal depth z f Under the given conditions, verify the position of the laser focus and make fine adjustments if necessary.

5. A lightweight laser femtosecond micro-engraving waveguide process according to claim 4, characterized in that: The focus depth of the combination is set to form a series of discrete modified points by controlling the number and interval of laser pulses, including the following steps: Determine the number of laser pulses N and the pulse interval t, and record the laser spot diameter D, and calculate the distance s between adjacent modified points using the formula s = v·t, where v is the laser scanning speed; The interval t of the laser pulses is adjusted by using the step distance s to ensure that the modified points are evenly distributed inside the material to form a predetermined lattice structure; Under the adjusted pulse interval t, the laser pulse parameters are fine-tuned as needed to optimize the uniformity and density of the lattice structure.

6. A lightweight laser femtosecond micro-engraving waveguide process according to claim 5, characterized in that: The method of using the formed lattice structure to construct a continuous waveguide path by continuously changing the position of the laser focus includes the following steps: Determine the predetermined geometry of the waveguide path, record the total length L of the path and the radius of curvature R of the path, and calculate the moving speed v of the laser focus on the path using the formula where t total is the time required to complete the path; Using the moving speed v, the scanning speed of the laser is adjusted to ensure that the laser focus moves continuously and evenly on the path to form a continuous waveguide path; At the adjusted scanning speed v, fine-tune the laser parameters as needed.

7. A lightweight laser femtosecond micro-engraving waveguide process according to claim 6, characterized in that: The step of optimizing the laser pulse parameters based on the constructed waveguide path comprises the following steps: Measuring the initial transmission efficiency η of the waveguide path o and loss coefficient α o ; Calculate the effect of laser pulse energy density E on transmission efficiency η, using the formula η=η o exp(-α o L), where L is the length of the waveguide path, the laser pulse energy density E is adjusted using the formula to maximize the transmission efficiency η and minimize the loss coefficient α o ; Under the adjusted laser pulse energy density E, the laser parameters are optimized.

8. A lightweight laser femtosecond micro-engraving waveguide process according to claim 7, characterized in that: The step of adjusting the waveguide path by optimizing the laser pulse parameters comprises the following steps: Determine the predetermined geometry and dimensions of the waveguide path, record the width and height h of the waveguide, and calculate the scanning path length L of the laser focus on the waveguide path scan , using the formula L scan =L+2h, where L is the total length of the waveguide path; Using the scan path length L scan , adjust the repetition frequency f of the laser pulse to ensure that the laser focus is evenly distributed on the waveguide path, using the formula f = L scan t, where v is the laser scanning speed and t is the pulse interval; Under the adjusted repetition frequency f, the laser parameters are fine-tuned as needed to achieve control of the waveguide shape and size.

9. A lightweight laser femtosecond micro-engraving waveguide process according to claim 8, characterized in that: The quality inspection of the entire waveguide structure comprises the following steps: Measure the transmittance T and reflectance R of the waveguide, and record the total loss α of the waveguide, calculate the transmission efficiency η of the waveguide, using the formula The transmission efficiency η is used to evaluate the continuity and optical performance of the waveguide to ensure that it meets the design standards. Based on the evaluated results, the overall performance of the waveguide is verified and optimized and adjusted as needed.

10. A lightweight laser femtosecond micro-engraving waveguide process according to claim 9, characterized in that: The method of correcting the waveguide structure that does not meet the standards according to the result of the quality inspection until all waveguides meet the preset performance indicators includes the following steps: Based on the quality inspection results, determine the waveguide structures that do not meet the standards in the waveguide, and record the locations and defect types of these parts; Based on the defect information, analyze the cause of the defect and use the formula ΔE=E opt -E actual , where E opt is the optimized laser pulse energy density, E actual is the actual laser pulse energy density used; Using the analysis results, adjust the laser pulse parameters, including energy density E, pulse interval t and scanning speed v, to eliminate or reduce defects; Under the adjusted parameter conditions, the waveguide is reprocessed and the continuity and optical performance of the waveguide are verified until all waveguides meet the preset performance indicators.

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